Occlusive medical device with fabric retention barb

ABSTRACT

An occlusive implant system may include a catheter having a lumen extending from a proximal opening to a distal opening, a core wire slidably disposed within the lumen, and an occlusive implant having an expandable framework configured to shift between a collapsed configuration and an expanded configuration, and an occlusive element disposed on the expandable framework. The expandable framework may include a plurality of anchor members extending radially outward from the expandable framework, at least some of the plurality of anchor members each have a barb projecting circumferentially therefrom. The occlusive implant may be releasably connected to a distal portion of the core wire.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 toU.S. Provisional Application Ser. No. 62/490,657, filed Apr. 27, 2017,the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates generally to percutaneous medical devices andmore particularly to percutaneous occlusive medical devices forimplantation into the left atrial appendage (LAA) of a heart.

BACKGROUND

Atrial fibrillation (AF) a common sustained cardiac arrhythmia affectingover 5.5 million people worldwide. Atrial fibrillation is the irregular,chaotic beating of the upper chambers of the heart. Electrical impulsesdischarge so rapidly that the atrial muscle quivers, or fibrillates.Episodes of atrial fibrillation may last a few minutes or several days.The most serious consequence of atrial fibrillation is ischemic stroke.It has been estimated that up to 20% of all strokes are related toatrial fibrillation. Most atrial fibrillation patients, regardless ofthe severity of their symptoms or frequency of episodes, requiretreatment to reduce the risk of stroke. The left atrial appendage (LAA)is a small organ attached to the left atrium of the heart as apouch-like extension. In patients suffering from atrial fibrillation,the left atrial appendage may not properly contract with the leftatrium, causing stagnant blood to pool within its interior, which canlead to the undesirable formation of thrombi within the left atrialappendage. Thrombi forming in the left atrial appendage may break loosefrom this area and enter the blood stream. Thrombi that migrate throughthe blood vessels may eventually plug a smaller vessel downstream andthereby contribute to stroke or heart attack. Clinical studies haveshown that the majority of blood clots in patients with atrialfibrillation are found in the left atrial appendage. As a treatment,medical devices have been developed which are positioned in the leftatrial appendage and deployed to close off the ostium of the left atrialappendage. Over time, the exposed surface(s) spanning the ostium of theleft atrial appendage becomes covered with tissue (a process calledendothelization), effectively removing the left atrial appendage fromthe circulatory system and reducing or eliminating the number of thrombiwhich may enter the blood stream from the left atrial appendage.

A continuing need exists for improved medical devices and methods tocontrol thrombus formation within the left atrial appendage of patientssuffering from atrial fibrillation.

SUMMARY

In a first aspect, an occlusive implant may comprise an expandableframework configured to shift between a collapsed configuration and anexpanded configuration, and an occlusive element disposed on theexpandable framework. The expandable framework may include a pluralityof anchor members extending radially outward from the expandableframework. At least some of the plurality of anchor members may eachhave a barb projecting circumferentially therefrom.

In addition or alternatively, and in a second aspect, each of theplurality of anchor members includes a body portion and a tip portion.

In addition or alternatively, and in a third aspect, the barb projectingcircumferentially from at least some of the plurality of anchor membersprojects from the body portion of its respective anchor member.

In addition or alternatively, and in a fourth aspect, the body portionof each anchor member is attached to the expandable framework at a baseof its respective anchor member.

In addition or alternatively, and in a fifth aspect, each barb includesa forward surface facing towards the tip portion of its respectiveanchor member, and a rear surface facing towards the base of itsrespective anchor member.

In addition or alternatively, and in a sixth aspect, the rear surface ispositioned at an obtuse angle to the body portion.

In addition or alternatively, and in a seventh aspect, the forwardsurface is positioned at an obtuse angle to the body portion.

In addition or alternatively, and in an eighth aspect, an intersectionof the forward surface with the rear surface forms a barb tip, the barbtip being rounded.

In addition or alternatively, and in a ninth aspect, each barb comprisesa semi-elliptical nub.

In addition or alternatively, and in a tenth aspect, the expandableframework and the plurality of anchor members are formed from a unitarytubular member.

In addition or alternatively, and in an eleventh aspect, an occlusiveimplant system may comprise a catheter having a lumen extending from aproximal opening to a distal opening, a core wire slidably disposedwithin the lumen, and an occlusive implant having an expandableframework configured to shift between a collapsed configuration and anexpanded configuration and an occlusive element disposed on theexpandable framework. The expandable framework may include a pluralityof anchor members extending radially outward from the expandableframework. At least some of the plurality of anchor members may eachhave a barb projecting circumferentially therefrom. The occlusiveimplant may be releasably connected to a distal portion of the corewire.

In addition or alternatively, and in a twelfth aspect, the occlusiveimplant is disposed within the lumen proximate the distal opening in thecollapsed configuration.

In addition or alternatively, and in a thirteenth aspect, a tip portionof each of the plurality of anchor members extends towards a proximalend of the occlusive implant.

In addition or alternatively, and in a fourteenth aspect, the occlusiveelement extends distally past all of the plurality of anchor members.

In addition or alternatively, and in a fifteenth aspect, the pluralityof anchor members each extend through the occlusive element.

In addition or alternatively, and in a sixteenth aspect, an occlusiveimplant may comprise an expandable framework configured to shift betweena collapsed configuration and an expanded configuration, and anocclusive element disposed over an outer surface of the expandableframework. The expandable framework may include a plurality of anchormembers extending radially outward from the expandable framework andthrough the occlusive element. At least some of the plurality of anchormembers may each have two barbs projecting circumferentially therefrom.

In addition or alternatively, and in a seventeenth aspect, each barbcomprises a semi-elliptical nub, each semi-elliptical nub on aparticular anchor member extending in a common circumferential directionfrom the particular anchor member.

In addition or alternatively, and in an eighteenth aspect, the two barbsextend in opposing circumferential directions from their respectiveanchor member.

In addition or alternatively, and in a nineteenth aspect, a distalportion of the occlusive element is attached to the expandable frameworkand attachment of the distal portion of the occlusive element to theexpandable framework is devoid of sutures and adhesives.

In addition or alternatively, and in a twentieth aspect, each of theplurality of anchor members has at least one barb projectingcircumferentially therefrom.

The above summary of some embodiments, aspects, and/or examples is notintended to describe each embodiment or every implementation of thepresent disclosure. The figures and the detailed description whichfollows more particularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description of various embodiments in connection withthe accompanying drawings, in which:

FIGS. 1-2 are side views of an example occlusive implant system;

FIG. 3 is a perspective view of an example occlusive implant;

FIG. 4 illustrates an example anchor member of the occlusive implant ofFIG. 3;

FIG. 5 is a flat pattern view of an example occlusive implant;

FIG. 5A is a flat pattern view of an alternative configuration of theexample occlusive implant of FIG. 5;

FIG. 6 is a detailed view of a portion of the flat pattern view of FIG.5;

FIG. 7 illustrates an alternative configuration of the detailed view ofFIG. 6;

FIG. 8 illustrates an alternative configuration of the detailed view ofFIG. 6;

FIG. 9 illustrates an alternative configuration of the detailed view ofFIG. 6;

FIGS. 10 and 11 illustrate alternative configurations of an anchormember for use with the occlusive implant of FIG. 3.

While aspects of the disclosure are amenable to various modificationsand alternative forms, specifics thereof have been shown by way ofexample in the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit aspects of thedisclosure to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of the disclosure.

DETAILED DESCRIPTION

The following description should be read with reference to the drawings,which are not necessarily to scale, wherein like reference numeralsindicate like elements throughout the several views. The detaileddescription and drawings are intended to illustrate but not limit theclaimed invention. Those skilled in the art will recognize that thevarious elements described and/or shown may be arranged in variouscombinations and configurations without departing from the scope of thedisclosure. The detailed description and drawings illustrate exampleembodiments of the claimed invention. However, in the interest ofclarity and ease of understanding, while every feature and/or elementmay not be shown in each drawing, the feature(s) and/or element(s) maybe understood to be present regardless, unless otherwise specified.

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about,” whether or not explicitly indicated. The term “about”, in thecontext of numeric values, generally refers to a range of numbers thatone of skill in the art would consider equivalent to the recited value(e.g., having the same function or result). In many instances, the term“about” may include numbers that are rounded to the nearest significantfigure. Other uses of the term “about” (e.g., in a context other thannumeric values) may be assumed to have their ordinary and customarydefinition(s), as understood from and consistent with the context of thespecification, unless otherwise specified.

The recitation of numerical ranges by endpoints includes all numberswithin that range, including the endpoints (e.g., 1 to 5 includes 1,1.5, 2, 2.75, 3, 3.80, 4, and 5).

Although some suitable dimensions, ranges, and/or values pertaining tovarious components, features and/or specifications are disclosed, one ofskill in the art, incited by the present disclosure, would understanddesired dimensions, ranges, and/or values may deviate from thoseexpressly disclosed.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise. It isto be noted that in order to facilitate understanding, certain featuresof the disclosure may be described in the singular, even though thosefeatures may be plural or recurring within the disclosed embodiment(s).Each instance of the features may include and/or be encompassed by thesingular disclosure(s), unless expressly stated to the contrary. Forsimplicity and clarity purposes, not all elements of the disclosedinvention are necessarily shown in each figure or discussed in detailbelow. However, it will be understood that the following discussion mayapply equally to any and/or all of the components for which there aremore than one, unless explicitly stated to the contrary. Additionally,not all instances of some elements or features may be shown in eachfigure for clarity.

Relative terms such as “proximal”, “distal”, “advance”, “retract”,variants thereof, and the like, may be generally considered with respectto the positioning, direction, and/or operation of various elementsrelative to a user/operator/manipulator of the device, wherein“proximal” and “retract” indicate or refer to closer to or toward theuser and “distal” and “advance” indicate or refer to farther from oraway from the user. In some instances, the terms “proximal” and “distal”may be arbitrarily assigned in an effort to facilitate understanding ofthe disclosure, and such instances will be readily apparent to theskilled artisan. Other relative terms, such as “upstream”, “downstream”,“inflow”, and “outflow” refer to a direction of fluid flow within alumen, such as a body lumen, a blood vessel, or within a device.

The term “extent” may be understood to mean a greatest measurement of astated or identified dimension, unless the extent or dimension inquestion is preceded by or identified as a “minimum”, which may beunderstood to mean a smallest measurement of the stated or identifieddimension. For example, “outer extent” may be understood to mean amaximum outer dimension, “radial extent” may be understood to mean amaximum radial dimension, “longitudinal extent” may be understood tomean a maximum longitudinal dimension, etc. Each instance of an “extent”may be different (e.g., axial, longitudinal, lateral, radial,circumferential, etc.) and will be apparent to the skilled person fromthe context of the individual usage. Generally, an “extent” may beconsidered a greatest possible dimension measured according to theintended usage, while a “minimum extent” may be considered a smallestpossible dimension measured according to the intended usage. In someinstances, an “extent” may generally be measured orthogonally within aplane and/or cross-section, but may be, as will be apparent from theparticular context, measured differently—such as, but not limited to,angularly, radially, circumferentially (e.g., along an arc), etc.

The terms “monolithic” and “unitary” shall generally refer to an elementor elements made from or consisting of a single structure or baseunit/element. A monolithic and/or unitary element shall excludestructure and/or features made by assembling or otherwise joiningmultiple discrete elements together.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment(s) described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it would be within the knowledge of oneskilled in the art to effect the particular feature, structure, orcharacteristic in connection with other embodiments, whether or notexplicitly described, unless clearly stated to the contrary. That is,the various individual elements described below, even if not explicitlyshown in a particular combination, are nevertheless contemplated asbeing combinable or arrangeable with each other to form other additionalembodiments or to complement and/or enrich the described embodiment(s),as would be understood by one of ordinary skill in the art.

For the purpose of clarity, certain identifying numerical nomenclature(e.g., first, second, third, fourth, etc.) may be used throughout thedescription and/or claims to name and/or differentiate between variousdescribed and/or claimed features. It is to be understood that thenumerical nomenclature is not intended to be limiting and is exemplaryonly. In some embodiments, alterations of and deviations frompreviously-used numerical nomenclature may be made in the interest ofbrevity and clarity. That is, a feature identified as a “first” elementmay later be referred to as a “second” element, a “third” element, etc.or may be omitted entirely, and/or a different feature may be referredto as the “first” element. The meaning and/or designation in eachinstance will be apparent to the skilled practitioner.

The occurrence of thrombi in the left atrial appendage (LAA) duringatrial fibrillation may be due to stagnancy of the blood pool in theLAA. The blood may still be pulled out of the left atrium by the leftventricle, however less effectively due to the irregular contraction ofthe left atrium caused by atrial fibrillation. Therefore, instead of anactive support of the blood flow by a contracting left atrium and leftatrial appendage, filling of the left ventricle may depend primarily orsolely on the suction effect created by the left ventricle. Further, thecontraction of the left atrial appendage may not be in sync with thecycle of the left ventricle. For example, contraction of the left atrialappendage may be out of phase up to 180 degrees with the left ventricle,which may create significant resistance to the desired flow of blood.Further still, most left atrial appendage geometries are complex andhighly variable, with large irregular surface areas and a narrow ostiumor opening compared to the depth of the left atrial appendage. Theseaspects as well as others, taken individually or in variouscombinations, may lead to high flow resistance of blood out of the leftatrial appendage.

In an effort to reduce the occurrence of thrombi formation within theleft atrial appendage and prevent thrombi from entering the blood streamfrom within the left atrial appendage, medical devices and/or occlusiveimplants have been developed that close off the left atrial appendagefrom the heart and/or circulatory system, thereby lowering the risk ofstroke due to thrombolytic material entering the blood stream from theleft atrial appendage. Additionally, to ease delivery and/or placementprocedures of the medical devices and/or occlusive implants, favorablenew features have been developed.

Turning now to the figures, FIGS. 1-3 illustrate an occlusive implantsystem 10 including a catheter 40 having a lumen 42 extending from aproximal opening to a distal opening, a core wire 30 slidably disposedwithin the lumen 42, and an occlusive implant 100 having an expandableframework 110 configure to shift between a collapsed configuration(e.g., FIG. 1), wherein the occlusive implant 100 is disposed within thelumen 42 proximate the distal opening in the collapsed configuration,and an expanded configuration (e.g., FIG. 2), and an occlusive element120 disposed on the expandable framework 110 (e.g., FIG. 3), wherein theocclusive implant 100 and/or the expandable framework 110 is configuredto shift between the collapsed configuration and the expandedconfiguration when the occlusive implant 100 is disposed distal of thedistal opening of the lumen 42 and/or the catheter 40, and/or when theocclusive implant 100 is unconstrained by the catheter 40. The occlusiveimplant 100 may be disposed at and/or releasably connected to a distalportion of the core wire 30. The core wire 30 may be slidably and/orrotatably disposed within the lumen 42 of the catheter 40. In someembodiments, a proximal end of the core wire 30 may extend proximally ofa proximal end of the catheter 40 and/or the proximal opening of thelumen 42 for manual manipulation by a clinician or practitioner. In someembodiments, the example occlusive implant 100 may be removablyattached, joined, or otherwise connected to the distal end of the corewire 30. Some suitable, but non-limiting, examples of materials for theocclusive implant system 10, the core wire 30, the catheter 40, and/orthe occlusive implant 100, etc. are discussed below. It is contemplatedthat any and/or all example occlusive implants disclosed herein may beused in accordance with and/or be associated with the example occlusiveimplant system 10 described above.

FIG. 3 illustrates some additional details of an example configurationof the occlusive implant 100 comprising the expandable framework 110configured to shift between the collapsed configuration and the expandedconfiguration. The expandable framework 110 may be compliant andsubstantially conform to and/or be in sealing engagement with the shapeand/or geometry of a lateral wall of a left atrial appendage in theexpanded configuration. In some embodiments, the occlusive implant 100may expand to a size, extent, or shape less than or different from amaximum unconstrained extent, as determined by the surrounding tissueand/or lateral wall of the left atrial appendage. Reducing a thicknessof various elements of the expandable framework 110 may increase theflexibility and compliance of the expandable framework 110 and/or theocclusive implant 100, thereby permitting the expandable framework 110and/or the occlusive implant 100 to conform to the tissue around it,rather than forcing the tissue to conform to the expandable framework110 and/or the occlusive implant 100.

The occlusive implant 100 may include the occlusive element 120 disposedon, disposed over, disposed about, or covering at least a portion of theexpandable framework 110. In some embodiments, the occlusive element 120may be disposed on, disposed over, disposed about or cover at least aportion of an outer (or outwardly-facing) surface of the expandableframework 110. In some embodiments, a proximal end of the expandableframework 110 may be configured to releasably attach, join, couple,engage, or otherwise connect to the distal end of the core wire 30. Insome embodiments, the proximal end of the expandable framework 110 mayinclude a threaded insert coupled thereto. In some embodiments, thethreaded insert may be configured to and/or adapted to couple with, jointo, mate with, or otherwise engage a threaded member disposed at thedistal end of the core wire 30. Other means of releasably couplingand/or engaging the proximal end of the expandable framework 110 to thedistal end of the core wire 30 are also contemplated.

In some embodiments, and as seen in FIG. 3, the expandable framework 110may include a plurality of anchor members 140 disposed about a peripheryof the expandable framework 110 in the expanded configuration, anexample of which may be seen in the detailed view of FIG. 4. Theplurality of anchor members 140 may extend radially outward from theexpandable framework 110. In some embodiments, at least some of theplurality of anchor members 140 may each have and/or include a bodyportion 142, a tip portion 144, and a barb 146 projectingcircumferentially therefrom, as shown in FIG. 4. In some embodiments,some and/or each of the plurality of anchor members 140 have at leastone barb 146 projecting circumferentially therefrom. Some suitable, butnon-limiting, examples of materials for the expandable framework 110,the plurality of anchor members 140, and/or the barb(s) 146, etc. arediscussed below.

The body portion 142 of each of the plurality of anchor members 140 maybe attached to the expandable framework 110 at a base 148 of itsrespective anchor member 140. The body portion 142 of each of theplurality of anchor members 140 may extend axially distally, toward thedistal end of the expandable framework 110 and/or the occlusive implant100, and/or in a distal direction from the base 148 of the anchor member140. The tip portion 144 of each of the plurality of anchor members 140may be formed with a curve or hook shape such that a free end of theanchor member 140 generally extends proximally and/or toward theproximal end of the expandable framework 110 and/or the occlusiveimplant 100, and the base 148 of the anchor member 140 may generally bedisposed proximal of the tip portion 144. In an alternative example, thetip portion 144 of each of the plurality of anchor members 140 may beformed with a generally straight or spear shape such that a free end ofthe anchor member 140 generally extends proximally and/or toward theproximal end of the expandable framework 110 and/or the occlusiveimplant 100, and the base 148 of the anchor member 140 is disposeddistally of the tip portion 144.

In some embodiments, each barb 146 projecting circumferentially from atleast some of the plurality of anchor members 140 projects from the bodyportion 142 of its respective anchor member 140. Each barb 146 mayproject from the body portion 142 of the anchor member 140 in acircumferential direction around the expandable framework 110 and/or acentral longitudinal axis of the occlusive implant 100. In at least someembodiments, the circumferential direction may be transverse, lateral,and/or generally perpendicular to the body portion 142 and/or the tipportion 144 of the anchor member 140.

Each barb 146 may include a forward surface 150 facing towards the tipportion 144 of its respective anchor member 140, and a rear surface 152facing towards the base 148 and/or the body portion 142 of itsrespective anchor member 140. The forward surface 150 may be positionedat an obtuse angle relative to the body portion 142 and/or the tipportion 144 of its respective anchor member 140. For example, theforward surface 150 may face distally and/or away from the base 148and/or the body portion 142, as well as circumferentially relative tothe body portion 142 of its respective anchor member 140 and/or thecentral longitudinal axis of the occlusive implant 100. In at least someembodiments, the rear surface 152 may be positioned at an obtuse anglerelative to the body portion 142 of its respective anchor member 140,and the forward surface 150 and the rear surface 152 may be angled toface in a common and/or the same circumferential direction. For example,the rear surface 152 may face proximally and/or toward the base 148and/or the body portion 142, as well as circumferentially relative tothe body portion 142 of its respective anchor member 140 and/or thecentral longitudinal axis of the occlusive implant 100. Alternatively,in some embodiments, the rear surface 152 may be positioned at an acuteangle or a right angle relative to the body portion 142 of itsrespective anchor member 140, and in embodiments with the acute angle,the forward surface 150 and the rear surface 152 may be angled to facein opposing circumferential directions. An intersection of the forwardsurface 150 with the rear surface 152 may form a barb tip 154. In atleast some embodiments, the barb tip 154 may be rounded. For example,the barb tip 154 may be formed with a radius of about 0.025 inches,0.015 inches, 0.010 inches, 0.005 inches, 0.002 inches, 0.001 inches, oranother suitable dimension as desired.

In some embodiments, the plurality of anchor members 140 may provide ananchoring mechanism to aid in retaining the occlusive implant 100 at atarget site within a patient's anatomy (i.e., the left atrial appendage,for example) in the expanded configuration. However, the barb(s) 146 maybe configured, positioned, and/or arranged such that engagement of thebarb(s) 146 with surrounding tissue at the target site is minimized oravoided. For example, the barb(s) 146 may not puncture, pierce, and/orextend into the surrounding tissue in the expanded configuration.Additionally, in some embodiments, the plurality of anchor members 140may provide an attachment mechanism for securing the occlusive element120 to the expandable framework 110.

Returning to FIG. 3, the occlusive element 120 may extend distally pastat least some of the plurality of anchor members 140. In someembodiments, the occlusive element 120 may extend distally past eachand/or all of the plurality of anchor members 140. In at least someembodiments, at least a distal portion of the occlusive element 120 maybe attached to the expandable framework 110. In some embodiments, atleast some of the plurality of anchor members 140 extend and/or projectthrough the occlusive element 120. In some embodiments, each and/or allof the plurality of anchor members 140 extend and/or project through theocclusive element 120. In some embodiments, the membrane or occlusiveelement may be attached to the frame at some and/or each of theplurality of anchor members 140, for example, by passing some and/oreach of the plurality of anchor members 140 through the occlusiveelement 120.

In some embodiments, the barb 146 on some and/or each of the at leastsome of the plurality of anchor members 140 may be disposed radiallyoutward of the occlusive element 120 and/or exterior of the occlusiveelement 120 while the base of its respective anchor member 140 isdisposed radially inward of and/or interior of the occlusive element120. The barb 146 may serve to retain the occlusive element 120 on theexpandable framework 110, thereby preventing the occlusive element 120from working loose and/or releasing from the expandable framework 110 asthe expandable framework 110 is shifted between the collapsedconfiguration and the expanded configuration. In some embodiments,attachment of the distal portion of the occlusive element 120 to theexpandable framework 110 is devoid of sutures and/or adhesives.

In one example, a frame path following along an outer surface of theexpandable framework 110 from the proximal end of the expandableframework 110 and/or the core wire 30 to the at least some of theplurality of anchor members 140 extending through the occlusive element120 may be longer than an occlusive element path following along anouter surface of the occlusive element 120 from the proximal end of theexpandable framework 110 and/or the core wire 30 to the at least some ofthe plurality of anchor members 140 extending through the occlusiveelement 120 when in the expanded configuration, because the outersurface of the expandable framework 110 may take a curving undulatingpath while the outer surface of the occlusive element 120 may take amore direct arcing path. As such, when the occlusive implant 100 and/orthe expandable framework 110 is shifted to the collapsed configurationfor delivery and/or disposal within the lumen 42 of the catheter 40, theocclusive element 120 may be placed in tension and/or stretched tightalong the outer surface of the expandable framework 110 and/or result ina portion of the expandable framework 110 deforming and/or bucklingunder the tension of the occlusive element 120. The tension may bereduced by extending and/or increasing the length of the occlusiveelement path (e.g., making the occlusive element 120 longer) whilekeeping and/or maintaining the length of the frame path (e.g., notchanging dimensions of the expandable framework). To accommodate thechanges in tension, the occlusive element 120 may be free to moveaxially along the body portion 142 of the at least some of the pluralityof anchor members 140 extending through the occlusive element 120. Forexample, the occlusive element 120 may be devoid of fixed attachment(e.g., may not be fixedly secured in place, such as with sutures oradhesives) to the plurality of anchor members 140 and/or the expandableframework 110. The barb(s) 146 may prevent the longer occlusive element120 from slipping off the at least some of the plurality of anchormembers 140 extending through the occlusive element 120 when theocclusive implant 100 and/or the expandable framework 110 is shifted tothe expanded configuration and the tension is released or reduced.

In some embodiments, the occlusive element 120 may be permeable orimpermeable to blood and/or other fluids, such as water. In someembodiments, the occlusive element 120 may include a polymeric membrane,a metallic or polymeric mesh, a porous filter-like material, or othersuitable construction. In some embodiments, the occlusive element 120prevents thrombi (i.e. blood clots, etc.) from passing through theocclusive element 120 and out of the left atrial appendage into theblood stream. In some embodiments, the occlusive element 120 promotesendothelization after implantation, thereby effectively removing theleft atrial appendage from the patient's circulatory system. Somesuitable, but non-limiting, examples of materials for the occlusiveelement 120 are discussed below.

FIG. 5 illustrates a flat pattern corresponding to one example of theexpandable framework 110 of the occlusive implant 100. The expandableframework 110 and the plurality of anchor members 140 may be integrallyformed and/or cut from a unitary member. In some embodiments, theexpandable framework 110 and the plurality of anchor members 140 may beintegrally formed and/or cut from a unitary tubular member andsubsequently formed and/or heat set to a desired shape in the expandedconfiguration. In some embodiments, the expandable framework 110 and theplurality of anchor members 140 may be integrally formed and/or cut froma unitary flat member, and then rolled or formed into a tubularstructure and subsequently formed and/or heat set to the desired shapein the expanded configuration. Some exemplary means and/or methods ofmaking and/or forming the expandable framework 110 include lasercutting, machining, punching, stamping, electro discharge machining(EDM), chemical dissolution, etc. Other means and/or methods are alsocontemplated.

In the example illustrated in FIG. 5, the plurality of anchor members140 comprises two rows of anchor members 140, and one row (e.g., aproximal row) of the plurality of anchor members 140 includes thebarb(s) 146. In another example, a distal row of the plurality of anchormembers 140 may include the barb(s) 146. In yet another example, bothrows of the plurality of anchor members 140, and/or all or each of theplurality of anchor members 140, may include the barb(s) 146, as shownin the flat pattern view of FIG. 5A. Alternatively, some (e.g., lessthan all) of the plurality of anchor members 140 in one or both rows ofthe plurality of anchor members 140 may include the barb(s) 146. Otherconfigurations are also contemplated.

FIG. 6 illustrates a detailed view of one example configuration of theplurality of anchor members 140 and barb(s) 146. As mentioned above,each barb 146 projects circumferentially from at least some of theplurality of anchor members 140 and may project from the body portion142 of its respective anchor member 140. Each barb 146 may include theforward surface 150 facing towards the tip portion 144 of its respectiveanchor member 140, and the rear surface 152 facing towards the base 148and/or the body portion 142 of its respective anchor member 140. In someembodiments, the forward surface 150 may be positioned and/or arrangedat an obtuse angle to an axis of the body portion 142 of its respectiveanchor member 140. In some embodiments, the forward surface 150 may bepositioned and/or arranged at an angle of about 130 to 170 degrees,about 140 to 160 degrees, about 150 degrees, etc. In some embodiments,the rear surface 152 may be positioned and/or arranged at an obtuseangle to an axis of the body portion 142 of its respective anchor member140. In some embodiments, the rear surface 152 may be positioned and/orarranged at an angle of about 95 to 130 degrees, about 100 to 120degrees, etc. The intersection of the forward surface 150 with the rearsurface 152 may form the barb tip 154, and in at least some embodiments,the barb tip 154 may be rounded. In some embodiments, the barb(s) 146may be configured such that the occlusive element 120 may be manuallyremoved from the plurality of anchor members 140 by a technician oroperator by manipulating the occlusive element 120 over and/or aroundthe barb(s) 146, but the occlusive element 120 is incapable of comingoff (e.g., falling off, etc.) of the plurality of anchor members 140 onits own. In an alternative example, some and/or each barb 146 maycomprise a semi-elliptical nub 156, as seen in FIG. 7. Otherconfigurations and/or arrangements are also contemplated.

In some embodiments, at least some of the plurality of anchor members140 may each have two barbs 146 projecting circumferentially therefrom.In one example, each barb may comprise a semi-elliptical nub 156,wherein each semi-elliptical nub 156 on a particular anchor member 140extends in a common circumferential direction from the particular anchormember 140, as shown in FIG. 8. In another example, shown in FIG. 9, thetwo barbs 146 may extend in opposing circumferential directions fromtheir respective anchor member 140 as substantially mirror images ofeach other in an “arrowhead” configuration, wherein each barb mayinclude the forward surface 150 facing towards the tip portion 144 ofits respective anchor member 140, and the rear surface 152 facingtowards the base 148 (not shown, see FIG. 6) and/or the body portion 142of its respective anchor member 140, as described above. In anotheralternative example, each of the two barbs 146 may be semi-ellipticalnubs extending in opposing circumferential directions from theirrespective anchor member 140. In yet another alternative example, eachof the plurality of anchor members 140 may be formed with an undulatingS-curve or zigzagging shape forming a plurality of projections extendingtransverse to the axis of the anchor member 140. The plurality ofprojections could be formed in a radial direction relative to thecentral longitudinal axis of the occlusive implant 100, acircumferential direction relative to the central longitudinal axis ofthe occlusive implant 100, both radial and circumferential directionsrelative to the central longitudinal axis of the occlusive implant 100,or in other configurations. Other configurations and/or arrangements arealso contemplated.

FIGS. 10 and 11 illustrate alternative examples of the plurality ofanchor members 140 and/or the barb(s) 146 projecting therefrom. The barb146 may project radially (e.g., in a radial direction, radially outward,radially inward, etc.) and/or axially from the body portion 142 and/orthe tip portion 144 of its respective anchor member 140 with respect tothe central longitudinal axis of the occlusive implant 100. In someembodiments, the barb 146 may project both circumferentially andradially from the body portion 142 and/or the tip portion 144 withrespect to the central longitudinal axis of the occlusive implant 100.In some embodiments, the barb 146 may be formed from within a part ofthe body portion 142 and/or the tip portion 144 of its respective anchormember 140. For example, a profile of the barb 146 may be cut within thebody portion 142 and/or the tip portion 144 such that when the anchormember 140 is formed into the curve or hook shape, or other suitableshape, the outline projects radially therefrom to form the barb 146. Insome embodiments, a distal tip of the barb 146 may project radiallyinward toward the central longitudinal axis of the occlusive implant 100and axially toward the proximal end of the occlusive implant 100. Otherconfigurations and/or arrangements are also contemplated.

The materials that can be used for the various components of theocclusive implant system 10, the core wire 30, the catheter 40, theocclusive implant 100, the expandable framework 110, the occlusiveelement 120, the plurality of anchor members 140, etc. (and/or othersystems or components disclosed herein) and the various elements thereofdisclosed herein may include those commonly associated with medicaldevices. For simplicity purposes, the following discussion makesreference to the occlusive implant system 10, the core wire 30, thecatheter 40, the occlusive implant 100, the expandable framework 110,the occlusive element 120, the plurality of anchor members 140, etc.However, this is not intended to limit the devices and methods describedherein, as the discussion may be applied to other elements, members,components, or devices disclosed herein, such as, but not limited to,the body portion 142, the tip portion 144, the barb 146, the base 148,the forward surface 150, the rear surface 152, the barb tip 154, etc.and/or elements or components thereof.

In some embodiments, the occlusive implant system 10, the core wire 30,the catheter 40, the occlusive implant 100, the expandable framework110, the occlusive element 120, the plurality of anchor members 140,etc., and/or components thereof may be made from a metal, metal alloy,polymer (some examples of which are disclosed below), a metal-polymercomposite, ceramics, combinations thereof, and the like, or othersuitable material. Some examples of suitable metals and metal alloysinclude stainless steel, such as 444V, 444L, and 314LV stainless steel;mild steel; nickel-titanium alloy such as linear-elastic and/orsuper-elastic nitinol; other nickel alloys such asnickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL®625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such asHASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copperalloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS®400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R44035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g.,UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys,other nickel-molybdenum alloys, other nickel-cobalt alloys, othernickel-iron alloys, other nickel-copper alloys, other nickel-tungsten ortungsten alloys, and the like; cobalt-chromium alloys;cobalt-chromium-molybdenum alloys (e.g., UNS: R44003 such as ELGILOY®,PHYNOX®, and the like); platinum enriched stainless steel; titanium;platinum; palladium; gold; combinations thereof; and the like; or anyother suitable material.

As alluded to herein, within the family of commercially availablenickel-titanium or nitinol alloys, is a category designated “linearelastic” or “non-super-elastic” which, although may be similar inchemistry to conventional shape memory and super elastic varieties, mayexhibit distinct and useful mechanical properties. Linear elastic and/ornon-super-elastic nitinol may be distinguished from super elasticnitinol in that the linear elastic and/or non-super-elastic nitinol doesnot display a substantial “superelastic plateau” or “flag region” in itsstress/strain curve like super elastic nitinol does. Instead, in thelinear elastic and/or non-super-elastic nitinol, as recoverable strainincreases, the stress continues to increase in a substantially linear,or a somewhat, but not necessarily entirely linear relationship untilplastic deformation begins or at least in a relationship that is morelinear than the super elastic plateau and/or flag region that may beseen with super elastic nitinol. Thus, for the purposes of thisdisclosure linear elastic and/or non-super-elastic nitinol may also betermed “substantially” linear elastic and/or non-super-elastic nitinol.

In some cases, linear elastic and/or non-super-elastic nitinol may alsobe distinguishable from super elastic nitinol in that linear elasticand/or non-super-elastic nitinol may accept up to about 2-5% strainwhile remaining substantially elastic (e.g., before plasticallydeforming) whereas super elastic nitinol may accept up to about 8%strain before plastically deforming. Both of these materials can bedistinguished from other linear elastic materials such as stainlesssteel (that can also be distinguished based on its composition), whichmay accept only about 0.2 to 0.44 percent strain before plasticallydeforming.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy is an alloy that does not show anymartensite/austenite phase changes that are detectable by differentialscanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA)analysis over a large temperature range. For example, in someembodiments, there may be no martensite/austenite phase changesdetectable by DSC and DMTA analysis in the range of about −60 degreesCelsius (° C.) to about 120° C. in the linear elastic and/ornon-super-elastic nickel-titanium alloy. The mechanical bendingproperties of such material may therefore be generally inert to theeffect of temperature over this very broad range of temperature. In someembodiments, the mechanical bending properties of the linear elasticand/or non-super-elastic nickel-titanium alloy at ambient or roomtemperature are substantially the same as the mechanical properties atbody temperature, for example, in that they do not display asuper-elastic plateau and/or flag region. In other words, across a broadtemperature range, the linear elastic and/or non-super-elasticnickel-titanium alloy maintains its linear elastic and/ornon-super-elastic characteristics and/or properties.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy may be in the range of about 50 to about 60 weightpercent nickel, with the remainder being essentially titanium. In someembodiments, the composition is in the range of about 54 to about 57weight percent nickel. One example of a suitable nickel-titanium alloyis FHP-NT alloy commercially available from Furukawa Techno Material Co.of Kanagawa, Japan. Other suitable materials may include ULTANIUM™(available from Neo-Metrics) and GUM METAL™ (available from Toyota). Insome other embodiments, a superelastic alloy, for example a superelasticnitinol can be used to achieve desired properties.

In at least some embodiments, portions or all of the occlusive implantsystem 10, the core wire 30, the catheter 40, the occlusive implant 100,the expandable framework 110, the occlusive element 120, the pluralityof anchor members 140, etc., and/or components thereof, may also bedoped with, made of, or otherwise include a radiopaque material.Radiopaque materials are understood to be materials capable of producinga relatively bright image on a fluoroscopy screen or another imagingtechnique during a medical procedure. This relatively bright image aidsa user in determining the location of the occlusive implant system 10,the core wire 30, the catheter 40, the occlusive implant 100, theexpandable framework 110, the occlusive element 120, the plurality ofanchor members 140, etc. Some examples of radiopaque materials caninclude, but are not limited to, gold, platinum, palladium, tantalum,tungsten alloy, polymer material loaded with a radiopaque filler, andthe like. Additionally, other radiopaque marker bands and/or coils mayalso be incorporated into the design of the occlusive implant system 10,the core wire 30, the catheter 40, the occlusive implant 100, theexpandable framework 110, the occlusive element 120, the plurality ofanchor members 140, etc. to achieve the same result.

In some embodiments, a degree of Magnetic Resonance Imaging (MM)compatibility is imparted into the occlusive implant system 10, the corewire 30, the catheter 40, the occlusive implant 100, the expandableframework 110, the occlusive element 120, the plurality of anchormembers 140, etc. For example, the occlusive implant system 10, the corewire 30, the catheter 40, the occlusive implant 100, the expandableframework 110, the occlusive element 120, the plurality of anchormembers 140, etc., and/or components or portions thereof, may be made ofa material that does not substantially distort the image and createsubstantial artifacts (e.g., gaps in the image). Certain ferromagneticmaterials, for example, may not be suitable because they may createartifacts in an MM image. The occlusive implant system 10, the core wire30, the catheter 40, the occlusive implant 100, the expandable framework110, the occlusive element 120, the plurality of anchor members 140,etc., or portions thereof, may also be made from a material that the MMmachine can image. Some materials that exhibit these characteristicsinclude, for example, tungsten, cobalt-chromium-molybdenum alloys (e.g.,UNS: R44003 such as ELGILOY®, PHYNOX®, and the like),nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R44035 such asMP35-N® and the like), nitinol, and the like, and others.

In some embodiments, the occlusive implant system 10, the core wire 30,the catheter 40, the occlusive implant 100, the expandable framework110, the occlusive element 120, the plurality of anchor members 140,etc., and/or portions thereof, may be made from or include a polymer orother suitable material. Some examples of suitable polymers may includepolytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE),fluorinated ethylene propylene (FEP), polyoxymethylene (POM, forexample, DELRIN® available from DuPont), polyether block ester,polyurethane (for example, Polyurethane 85A), polypropylene (PP),polyvinylchloride (PVC), polyether-ester (for example, ARNITEL®available from DSM Engineering Plastics), ether or ester basedcopolymers (for example, butylene/poly(alkylene ether) phthalate and/orother polyester elastomers such as HYTREL® available from DuPont),polyamide (for example, DURETHAN® available from Bayer or CRISTAMID®available from Elf Atochem), elastomeric polyamides, blockpolyamide/ethers, polyether block amide (PEBA, for example availableunder the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA),silicones, polyethylene (PE), Marlex high-density polyethylene, Marlexlow-density polyethylene, linear low density polyethylene (for exampleREXELL®), polyester, polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polytrimethylene terephthalate, polyethylenenaphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI),polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide(PPO), poly paraphenylene terephthalamide (for example, KEVLAR®),polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMSAmerican Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinylalcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS50A), polycarbonates, ionomers, polyurethane silicone copolymers (forexample, ElastEon® from Aortech Biomaterials or ChronoSil® fromAdvanSource Biomaterials), biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like. In some embodiments, the sheath can be blendedwith a liquid crystal polymer (LCP). For example, the mixture cancontain up to about 6 percent LCP.

In some embodiments, the occlusive implant system 10, the core wire 30,the catheter 40, the occlusive implant 100, the expandable framework110, the occlusive element 120, the plurality of anchor members 140,etc. may include a textile material. Some examples of suitable textilematerials may include synthetic yarns that may be flat, shaped, twisted,textured, pre-shrunk or un-shrunk. Synthetic biocompatible yarnssuitable for use in the present invention include, but are not limitedto, polyesters, including polyethylene terephthalate (PET) polyesters,polypropylenes, polyethylenes, polyurethanes, polyolefins, polyvinyls,polymethylacetates, polyamides, naphthalene dicarboxylene derivatives,natural silk, and polytetrafluoroethylenes. Moreover, at least one ofthe synthetic yarns may be a metallic yarn or a glass or ceramic yarn orfiber. Useful metallic yarns include those yarns made from or containingstainless steel, platinum, gold, titanium, tantalum or a Ni—Co—Cr-basedalloy. The yarns may further include carbon, glass or ceramic fibers.Desirably, the yarns are made from thermoplastic materials including,but not limited to, polyesters, polypropylenes, polyethylenes,polyurethanes, polynaphthalenes, polytetrafluoroethylenes, and the like.The yarns may be of the multifilament, monofilament, or spun-types. Thetype and denier of the yarn chosen may be selected in a manner whichforms a biocompatible and implantable prosthesis and, more particularly,a vascular structure having desirable properties.

In some embodiments, the occlusive implant system 10, the core wire 30,the catheter 40, the occlusive implant 100, the expandable framework110, the occlusive element 120, the plurality of anchor members 140,etc. may include and/or be treated with a suitable therapeutic agent.Some examples of suitable therapeutic agents may includeanti-thrombogenic agents (such as heparin, heparin derivatives,urokinase, and PPack (dextrophenylalanine proline argininechloromethylketone)); anti-proliferative agents (such as enoxaparin,angiopeptin, monoclonal antibodies capable of blocking smooth musclecell proliferation, hirudin, and acetylsalicylic acid);anti-inflammatory agents (such as dexamethasone, prednisolone,corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine);antineoplastic/antiproliferative/anti-mitotic agents (such aspaclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine,epothilones, endostatin, angiostatin and thymidine kinase inhibitors);anesthetic agents (such as lidocaine, bupivacaine, and ropivacaine);anti-coagulants (such as D-Phe-Pro-Arg chloromethyl keton, an RGDpeptide-containing compound, heparin, anti-thrombin compounds, plateletreceptor antagonists, anti-thrombin antibodies, anti-platelet receptorantibodies, aspirin, prostaglandin inhibitors, platelet inhibitors, andtick antiplatelet peptides); vascular cell growth promoters (such asgrowth factor inhibitors, growth factor receptor antagonists,transcriptional activators, and translational promoters); vascular cellgrowth inhibitors (such as growth factor inhibitors, growth factorreceptor antagonists, transcriptional repressors, translationalrepressors, replication inhibitors, inhibitory antibodies, antibodiesdirected against growth factors, bifunctional molecules consisting of agrowth factor and a cytotoxin, bifunctional molecules consisting of anantibody and a cytotoxin); cholesterol-lowering agents; vasodilatingagents; and agents which interfere with endogenous vascoactivemechanisms.

While the discussion above is generally directed toward an occlusiveimplant for use in the left atrial appendage of the heart, theaforementioned features may also be useful in other types of medicalimplants where a fabric or membrane is attached to a frame or supportstructure including, but not limited to, implants for the treatment ofaneurysms (e.g., abdominal aortic aneurysms, thoracic aortic aneurysms,etc.), replacement valve implants (e.g., replacement heart valveimplants, replacement aortic valve implants, replacement mitral valveimplants, replacement vascular valve implants, etc.), and/or other typesof occlusive devices (e.g., atrial septal occluders, cerebral aneurysmoccluders, peripheral artery occluders, etc.). Other useful applicationsof the disclosed features are also contemplated.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of theinvention. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. An occlusive implant, comprising: an expandableframework configured to shift between a collapsed configuration and anexpanded configuration; and an occlusive element disposed on theexpandable framework; wherein the expandable framework includes aplurality of anchor members extending radially outward from theexpandable framework; wherein at least some of the plurality of anchormembers each have a barb projecting circumferentially therefrom.
 2. Theocclusive implant of claim 1, wherein each of the plurality of anchormembers includes a body portion and a tip portion.
 3. The occlusiveimplant of claim 2, wherein the barb projecting circumferentially fromat least some of the plurality of anchor members projects from the bodyportion of its respective anchor member.
 4. The occlusive implant ofclaim 2, wherein the body portion of each anchor member is attached tothe expandable framework at a base of its respective anchor member. 5.The occlusive implant of claim 2, wherein each barb includes a forwardsurface facing towards the tip portion of its respective anchor member,and a rear surface facing towards the base of its respective anchormember.
 6. The occlusive implant of claim 5, wherein the rear surface ispositioned at an obtuse angle to the body portion.
 7. The occlusiveimplant of claim 5, wherein the forward surface is positioned at anobtuse angle to the body portion.
 8. The occlusive implant of claim 5,wherein an intersection of the forward surface with the rear surfaceforms a barb tip, the barb tip being rounded.
 9. The occlusive implantof claim 1, wherein each barb comprises a semi-elliptical nub.
 10. Theocclusive implant of claim 1, wherein the expandable framework and theplurality of anchor members are formed from a unitary tubular member.11. An occlusive implant system, comprising: a catheter having a lumenextending from a proximal opening to a distal opening; a core wireslidably disposed within the lumen; and an occlusive implant having anexpandable framework configured to shift between a collapsedconfiguration and an expanded configuration, and an occlusive elementdisposed on the expandable framework; wherein the expandable frameworkincludes a plurality of anchor members extending radially outward fromthe expandable framework, at least some of the plurality of anchormembers each have a barb projecting circumferentially therefrom; whereinthe occlusive implant is releasably connected to a distal portion of thecore wire.
 12. The occlusive implant system of claim 11, wherein theocclusive implant is disposed within the lumen proximate the distalopening in the collapsed configuration.
 13. The occlusive implant systemof claim 11, wherein a tip portion of each of the plurality of anchormembers extends towards a proximal end of the occlusive implant.
 14. Theocclusive implant system of claim 11, wherein the occlusive elementextends distally past all of the plurality of anchor members.
 15. Theocclusive implant system of claim 11, wherein the plurality of anchormembers each extend through the occlusive element.
 16. An occlusiveimplant, comprising: an expandable framework configured to shift betweena collapsed configuration and an expanded configuration; and anocclusive element disposed over an outer surface of the expandableframework; wherein the expandable framework includes a plurality ofanchor members extending radially outward from the expandable frameworkand through the occlusive element; wherein at least some of theplurality of anchor members each have two barbs projectingcircumferentially therefrom.
 17. The occlusive implant of claim 16,wherein each barb comprises a semi-elliptical nub, each semi-ellipticalnub on a particular anchor member extending in a common circumferentialdirection from the particular anchor member.
 18. The occlusive implantof claim 16, wherein the two barbs extend in opposing circumferentialdirections from their respective anchor member.
 19. The occlusiveimplant of claim 16, wherein a distal portion of the occlusive elementis attached to the expandable framework and attachment of the distalportion of the occlusive element to the expandable framework is devoidof sutures and adhesives.
 20. The occlusive implant of claim 16, whereineach of the plurality of anchor members has at least one barb projectingcircumferentially therefrom.